Countries trade with each-other, and trade is in the context of goods, services, labour and many other things. They trade with each other because they’re different, and have different tastes and preferences, different attitudes towards risk, different technological frontiers, different resources, different climate and ecologies and so on. It’s differences in tastes and preferences, resources and technology together with ways of thinking (manifesting in managerial and design differences) which are the reasons countries benefit when they trade with each other in goods, services, finance and labour.